gravity

Certain weird gravity conditions would make it possible to travel through a wormhole and back.

Here's why the force of gravity pulls us down rather than up. The answer involves Einstein and the bendy realm of space-time.

Earth is spherical, but what would happen if the Earth were flat? We explore some of the bizarre implications of a flat world which would make life as we know it virtually impossible.

Some of Hawking's theories revolutionized the way we view the universe, but others still leave scientists scratching their heads.

Scientists have used computer models to predict the size of minuscule deformations, or mountains, on the surfaces of neutron stars, which are responsible for causing gravitational waves as they spin.

Why is the universe the way it is? Over the years, scientists have explored many ways to explain the cosmos, leading to some crazy-sounding ideas.

Here's how we might stop the flow of time.

A simulated binary system animation shows how extreme gravity warps two black holes locked in a mesmerizing "dance."

Walking around the moon could be faster than we originally thought, but actually doing it would require some serious planning.

Scientists analyzed the hearts of retired astronaut Scott Kelly after he spent time in space and elite endurance swimmer Benoît Lecomte after he swam the Pacific Ocean.